1. Field of the Invention
The present invention is broadly concerned with manway assemblies adapted for mounting within an opening provided in a vessel wall or the like in order to provide selective access to the interior of the vessel. More particularly, the invention pertains to such manway assemblies which are equipped with an inner manway cover that may be selectively opened from the exterior of the vessel to provide access; preferably, the inner cover is swingably mounted for movement between a closed and an open position, and wherein the cover is supported by a swing mount including a pivotal support arm and a coupler which are telescopically interfitted. Such a cover support permits ready adjustment and/or removal of the manway cover as necessary.
2. Discussion of Prior Art
Large vessels such as holding tanks or petroleum transfer conduits are normally equipped with manways permitting access to the interior of the vessels for repair or inspection purposes. Such manways come in a variety of styles. The most simple manway involves use of a cover which may be bolted to an upstanding annular flange. In other applications, however, it is desirable to have an internal cover. For example, in high pressure vessels, it is advantageous to equip a manway assembly with an internal cover so that vessel pressure assists in providing a high-integrity seal. Such internal cover manway assemblies are known. However, in general they are characterized by a very complex construction and difficulty in installation. A particular problem with such prior assemblies is the fact that the internal manway cover is hingedly mounted to a manway ring or the like. In such instances it is difficult to adjust the inner cover to provide the best possible seal.
In addition, some prior internal cover manway assemblies cannot be readily opened or manipulated from a position exterior to the vessel. As a consequence, while the use of internal cover manway assemblies is in many cases preferred, the cost and complexity of prior assemblies of this type has detracted from the usefulness thereof.
The present overcomes the problems outlined above and provides an improved manway assembly adapted for mounting within an opening provided in a vessel wall or the like, in order to provide selective access to the interior of the vessel. The manway assembly broadly includes a ring having a circular or round outer periphery and an inner passageway therethrough, with the ring adapted for securement proximal to a wall opening in order to present an inner surface adjacent the vessel interior and an opposed outer surface. The overall assembly further includes an internal cover sized to engage the ring inner surface and cover the passageway. The internal cover is preferably secured via a swing mount supporting the cover from movement between a passageway-covering position in engagement with the ring inner surface, in an open position allowing access to the vessel interior through the passageway. The swing mount includes a pivotal cover-supporting arm and a coupler, with the arm and coupler being telescopically interfitted and relatively separable to permit adjustment and/or removal of the internal cover. Finally, the overall assembly includes a cover lock operable to releasibly lock the cover in the passageway-covering position thereof. Further, this lock is manipulable from outside the vessel to selectively unlock the cover and allow movement thereof.
In preferred forms, the cover swing mount comprises a tubular member fixedly secured adjacent the manway assembly ring, with the arm supporting the cover telescopically received within the tubular member. In the fashion, the swing mount for the cover is in the form of a davit-type assembly.
Both the inner manway cover and the passageway provided through the circular manway ring are of oval configuration. In this way, the manway cover may be detached and passed through the oval opening for repair or replacement purposes.
The cover lock is preferably in the form of a bolt plate swingably mounted adjacent the manway ring outer surface and having at least one bolt-receiving bore therethrough. A threaded bolt shank is secured to the outer face of the cover and is adapted to extend through the passageway and plate bore. A nut is threaded onto the bolt to interconnect the cover and bolt plate. Normally, the bolt plate has a plurality of circumferentially spaced bores therethrough, whereas the cover is equipped with a like number of outwardly extending threaded studs. The latter are preferably threaded into corresponding blind bores in the manway cover, and can be detached as necessary from the cover. To this end, the outer ends of the threaded studs are provided with square or hexagonal ends, thereby facilitating wrench-removal thereof.
The bolt plate is also preferably mounted using a davit-type mounting arrangement very similar to that employed for the internal manway cover. Thus, the bolt plate is supported on a swingable arm, the latter being telescopically received within an external tubular member.